BlueRu Posted January 5, 2011 Share Posted January 5, 2011 (edited) Problem Car: 86 Brat 4wd 1.8 OHV w/lifters 5-sp Manual Webber carb. from redline (under 2 years old) Problem started the other day. 1st start of the day, no problems. I made a short trip into town that did not require me to turn the car off. I got home, made a sandwich - ate lunch. Went out about 30 min later, turn the key, she makes all the normal starting sounds, just wont fire up. Looked under the hood, nothing obviously wrong there. checked connections, made sure things were plugged in nice and tight. Tried to start again, still no luck. Starting while pumping the gas seem to make it want to turn over more, as the starter seems to work a little faster, almost sounded a little closer to actually starting. During one of these starting & pumping gas sessions, it actually fired up. It idled normally. I decided to test drive it. Took it about 10 min. down the road, then i started to smell a burning smell - similar to plastic or rubber. The car began to misfire violently while i was going about 30mph. Engine then died completely. Tried to restart while coasting, no luck. Tried to pop the cluch while coasting, still didnt start. It had reverted back to being unable to start. She will start up normal the 1st start of the day. Normal is: Turn the key, fires up in under a second - never hard to start. She drives normal throughout that 1st start. Has a pre-existing condition of low compression in a cylinder, and bad rings in another, all on the same driver side - so it drives similar to when your 1st learning to drive a manual transmission - a little jerky. If I turn the Brat off, then turn it on immediately - it starts normally. But let it sit for a while, then no start. Checked: -fuel flow: 4 psi into carb. When both barrels wide open, fuel psi drops to 3 holds steady. -choke: appears to be set correctly. no binding on levers. choke supply voltage stable at 11.74 -all vacuum lines tight -air filter clean -fuses and fuseable links good -distrib looks good. nothing melted or burnt (cap & rotor 1 year old). Distrib cables are fairly new (just over a year) and they are not frayed or cracked, they still fit tight on the plugs and cap. distrib wire harness was replaced about a year ago -spark plugs just over a year old. still getting spark - not sure how strong though Any ideas on what to check next, possible solutions, or other topics to search here on the board, please let me know Thanks BlueRu Edited January 6, 2011 by BlueRu Quote Link to comment Share on other sites More sharing options...
skishop69 Posted January 5, 2011 Share Posted January 5, 2011 You've got a coil, ground or disty problem. You're getting spark, but after it heats up and whatever it is goes to hell, it's too weak to do any good. When it does this hot (won't start) pull a plug and watch the color of the spark with someone cranking it. It should be an orangish color. White or blue spark is too weak. Check the connections on the coil and disty, grounds from the battery to block and body. Most likely, it's the coil getting weak. Could be the condensor/ignitor too. Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 5, 2011 Author Share Posted January 5, 2011 ok, thanks. I'll Test then report as soon as i can! Quote Link to comment Share on other sites More sharing options...
naru Posted January 5, 2011 Share Posted January 5, 2011 Doubt it is a spark issue,but,worth checking for the time it takes. Blue=good, Orange=bad Better indicator of spark strength is the size of gap it will jump. A cheapo spark tester like this is a great tool. http://cgi.ebay.com/ebaymotors/Thexton-404-Adjustable-Ignition-Spark-Tester-_W0QQcmdZViewItemQQhashZitem5d2a123007QQitemZ400137793543QQptZMotorsQ5fAutomotiveQ5fTools Sounds more like it is flooding. Fuel pressure is a little high. You should not see a "steady stream into barrels at idle". Fuel should only enter below the throttle plate at idle. Burning plastic smell is suggestive of the infamous ASV reed valve meltdown. Search for ASV for more on that. Quote Link to comment Share on other sites More sharing options...
naru Posted January 5, 2011 Share Posted January 5, 2011 You may find what Briggs and Stratton says about spark colour interesting. "A bright blue spark is best. A yellow/orange spark signifies weak ignition. Not true. Spark color determines virtually nothing. The hottest spark is ultraviolet which we can't see. Blue spark is cold in comparison to ultra-violet. Orange and yellow come from particles of sodium in the air ionizing in the high energy of the spark gap." Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 6, 2011 Author Share Posted January 6, 2011 (edited) Well im glad that i tried testing the spark at night, cause its obvious that my distrib cables are not in good shape. its arcing everywhere. Whats a good set of cables to buy? a good balance of quality and price spark color looked orange. but i would want to retest after i get better cables. Naru, Thanks for the tip, I will probably buy that little gizmo. I dont think that its flooding, steady stream was a poor choice of words - sorry. its been working great since i put on the weber. I am not getting a strong gas odor Edited January 6, 2011 by BlueRu Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 10, 2011 Author Share Posted January 10, 2011 Got a new set of cables (ThunderCore wire). Much better quality than my other ones. After I installed, I did notice an improvement in the problem, how ever it is still present. of course the 1st start of the day starts fine. The change occurs when i go start it after sitting about 30min. Now It will start, but only for a splt second, then the rpm gauge drops to zero, and then the engine dies. it will not start after this - back to its condition mentioned in above posts. Its odd that the rpm gauge goes to zero, then immediately the engine stalls. Normally the rpm gauge moves in sync with the starting of the car, now the rpm gauge does not move at all with the starting of the car. im not a mechanic but i fell like the problem is in the ignition switch, thats why the gauge drops to zero. any thoughts on what to do? Quote Link to comment Share on other sites More sharing options...
kanurys Posted January 10, 2011 Share Posted January 10, 2011 This is a long shot, but perhaps the exhaust is partially clogged (at the cat?). It gets worse when hot and expanded and startes pushing exhaust back through the reed valves also causing the reed valve burning. This is totally speculation - but maybe check the exhaust flow when warmed up. Also see what is coming out of the reed valves (air suck valves) at their intake at the air cleaner (or what ever it is since you have a weber). Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 10, 2011 Author Share Posted January 10, 2011 I had a complete exhaust system block-up about 4 years ago when i was on the highway. The car still ran, I just couldnt drive it over about 25mph. I had the entire exhaust system replaced. Because of the Weber conversion, most of that stuff was removed or blocked off anyway. Good suggestion, I just dont think thats it. I can still start the car in the morning at drive it at length with no problems. Its just the stopping for a while and restarting seems to be where the problem starts. Thanks though! Quote Link to comment Share on other sites More sharing options...
naru Posted January 10, 2011 Share Posted January 10, 2011 Check for spark when it doesn`t start. Quote Link to comment Share on other sites More sharing options...
Phizinza Posted January 10, 2011 Share Posted January 10, 2011 My mate had trouble starting when warm after he put a weber on the car. I think it turned out he didn't have the insulator spacer between the carb and manifold. The carb was getting very hot and the fuel inside the float bowl was vaporizing and building up pressure pushing out the jets and pouring into the manifold basically flooding it. But then at the same time emptying the float bowl and that would take a little while to refill. Just a thought. Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 10, 2011 Author Share Posted January 10, 2011 No spark at plugs when warm. From what you said and what i read around here, the coil is the 1st thing to check. im not sure how to test it. Ill see if i can find my Chilton (or whatever) manual..... Quote Link to comment Share on other sites More sharing options...
naru Posted January 11, 2011 Share Posted January 11, 2011 Check for 12V at coil -,key on,when no spark. If yes,coil probably OK. Look for pulses at coil - w/a test light while cranking. Light on no flashing=bad ignition module. Quote Link to comment Share on other sites More sharing options...
87glsubie Posted January 11, 2011 Share Posted January 11, 2011 not real bright with these but maybe theres some thermal expansion going on. maybe in the disty. not sure how the pic up is for crank positon but if the gap is to big it wont get a good signal. pretty far fetched though. i think this because it only does it when it gets warm. but it runs when its warm as long as its not shut off so that totally throws my idea out the window. i agree with what he said ^^^^^^. Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 11, 2011 Author Share Posted January 11, 2011 using test lamp and the (2) + & - terminals on the Coil: 1st start of the day = Flashing lights. They flash insync with the rpm of the engine. After letting it sit, so the car is in its non starting mode = no Flashing lights. Still get 12v though the center terminal with the ignition on in both cases. This means i need a coil? Quote Link to comment Share on other sites More sharing options...
naru Posted January 11, 2011 Share Posted January 11, 2011 If the test light does not light up when connected between battery negative and coil negative w/key on,coil is fried provided it does light up when connected to coil positive and battery negative. Light on,no flashing while cranking(probe on coil negative,lead on battery negative) indicates an ignition module problem. Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 11, 2011 Author Share Posted January 11, 2011 While the brat was still in its non starting state (warm) I took the additional readings: With ignition switch to "on": -testing between coil neg + battery neg gives me a steady light on and showing 12v -testing between coil pos + battery neg also gives steady light on and showing 12v While turning the ignition to "start" and holding, testing between the coil neg + battery negative the light stays on, but dims a little showing a 12v to 10v drop. doesnt pulse, just a steady 10v when starting Quote Link to comment Share on other sites More sharing options...
naru Posted January 11, 2011 Share Posted January 11, 2011 Sounds like the module wonks out when warm.The light should flicker. Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 12, 2011 Author Share Posted January 12, 2011 Naru are you referring to the ignition coil as a module or the module inside the Distrib? im thinking of just replacing the coil with a new one, and getting a reman or rebuilt distributor. I know this coil was replaced like 4-5 years ago, and the distrib im sure is original. I have close to 255k on the brat (although the mileage gauge doesnt work intermittently). Do you know any place to get a new distrib. wire harness? I rewired mine a few years back, but i was still unable to find those 90* connectors small enough for inside the distributor, so i had to reuse them. Thanks for all your help - excellent accuracy! Quote Link to comment Share on other sites More sharing options...
naru Posted January 12, 2011 Share Posted January 12, 2011 The module inside the Distrib. Junkyard or dealer for the harness. Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 12, 2011 Author Share Posted January 12, 2011 found a used distrib. in the garage but it has a lot of play in the shaft. I installed it anyway just to see if the different ignition module would change the Brats behavior, and so far i have been able to start the car just fine when its warm. im confident is saying that the ignition module was indeed the culprit. i'll just pirate the module off it, and put it in my old one and hopefully be done with it. a cheap fix so far.... Quote Link to comment Share on other sites More sharing options...
BlueRu Posted January 13, 2011 Author Share Posted January 13, 2011 Finished transplanting the ignition module, she now runs normal! Starts every time again! Many Thanks Naru! Quote Link to comment Share on other sites More sharing options...
naru Posted January 13, 2011 Share Posted January 13, 2011 Glad it worked out for you. We like happy endings. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.